材料期刊网

Numerical analysis on rotary forging mechanism of a flange

Gang LIU , Shijian YUAN , Mingxue ZHANG , Longbiao CHI

材料科学技术（英文）

A numerical simulation on the rotary forging process of a flange is conducted by three-dimensional rigid-plastic finite element method. The states of stress and strain rate in the workpiece are analyzed and the forging mechanism of the flange is revealed. Moreover, the influence of the die configuration on the material flow is also analyzed.

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Studies of the anion position parameter chi of the ternary semiconductor CuGaS2 by use of Ni+ ion probe

Materials Science and Engineering B-Solid State Materials for Advanced Technology

The anion position parameter chi of NiS4 cluster formed in the ternary semiconductor CuGaS2 by substitution of Ni+ for Cu+ has been determined by studying the optical spectra and EPR data for CuGaS2:Ni+. The result (chi approximate to 0.263(1)) is consistent with the mean value of the X-ray measurement results reported in two groups of references and also with the calculated value obtained from the conservation of tetrahedral bonds (CTB) plus eta = eta(tet) rule (where eta = c/2a). So, we suggest that the anion position parameter chi in pure CuGaS2 crystal is close to the above value obtained by use of Ni+ ion probe. The optical absorption bands and g factors g(parallel to), g(perpendicular to), of CuGaS2: Ni+ are therefore explained reasonably from the anion position parameter. (C) 2003 Elsevier B.V. All rights reserved.

关键词: structural parameter;electron paramagnetic resonance (EPR);optical;spectrum crystal-field theory;CuGaS2;Ni+;chalcopyrite semiconductors;superposition model;crystal

Influences of variations of characteristic parameters of protein molecules on states of soliton transported bio-energy

International Journal of Modern Physics B

We simulate numerically the dynamic properties of new soliton with quasi-coherent two quanta in the improved model by fourth-order Runge-Kutta way. We observed that the window of formation of new soliton is shifted toward smaller values of coupling constants when compared with the Davydov's soliton with one quantum and Forner's soliton with two quantum model. The new soliton formation starts at (chi 1 + chi 2) = 20 PN, and pinning starts from (chi 1 + chi 2) = 86 PN. The pinned solitons are also observed if both quanta are on the same end of the chain in the initial state. The behaviors of new soliton are varied under influences for variations of characteristic parameters arising from the structure nonuniformity of protein molecules. Although the new soliton is also sensitive to the dipole-dipole interaction and diagonal disorder, the sensitivity to the impurity is weaker than that of the Davydov's and Forner's solitons. Therefore, the new soliton is robust against the fluctuations of coupled constant, dipole-dipole interaction and diagonal disorder arising from the impurity or structure nonuniformity, when compared with that of the Davydov's and Forner's solitons.

关键词: protein;bio-energy transport;soliton;structure nonuniformity;characteristic parameter;davydov soliton;living systems;improved model;thermodynamic;properties;biological temperature;finite-temperature;quantum;dynamics;disorder;lifetime

Effects of Mo on the Precipitation Behaviors in High-Nitrogen Austenitic Stainless Steels

Feng Shi

材料科学技术（英文）

Precipitation behaviors of Fe-18Cr-18Mn-0.63N and Fe-18Cr-18Mn-2Mo-0.69N high-nitrogen austenitic stainless steels during isothermally aging at 850°C have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The experimental results show that precipitation displays a discontinuous cellular way and the precipitates are identified as Cr₂N in Fe-18Cr-18Mn-0.63N steel. The addition of Mo makes precipitation occur not only at the grain boundary but also inside the grain and precipitation also displays discontinuous cellular way. The precipitates at the grain boundary and in the cell are both identified as Cr₂N phase and χ phase and the precipitates inside the grain are identified as Χ phase in Fe-18Cr-18Mn-2Mo-0.69N steel. The nucleations of  Χ phase and Cr₂N phase at the grain boundary are both governed by the diffusion of Cr atoms. The formation and growth of χ phase inside the grain are induced by the impoverishment of N atoms with increasing aging time.

关键词: Austenitic stainless steel

时效温度对铸造超级双相不锈钢析出相的影响

向红亮何福善刘东

金属学报

对固溶处理后的铸造超级双相不锈钢材料进行时效处理, 利用OM, SEM, XRD和TEM分析了时效温度对析出相的影响. 结果表明, 固溶后经时效处理, 金属间相在铁素体内和铁素体/奥氏体晶界析出; 650℃时效时, 析出的金属间相主要是χ相; 750℃时效时析出σ相和χ相, 此时σ相由χ相演变而来; 850℃时效下则直接析出σ相; 950℃时效后, 少量的σ相仅在铁素体/奥氏体晶界产生.

关键词: 铸造超级双相不锈钢 , aging temperatures , σ phase , χ phase

冷却速率对GWZ1032K合金中14H-LPSO结构形成的影响

张松袁广银卢晨丁文江

金属学报 doi:10.3724/SP.J.1037.2010.00177

采用金属型铸造和慢速凝固, 在不同冷却速率下制备了Mg-10Gd-3Y-1.8Zn-0.5Zr(质量分数, %) (GWZ1032K)合金. 采用SEM, TEM和XRD研究了冷却速率不同的GWZ1032K 合金的组织和相构成. 在GWZ1032K合金中, α-Mg基体中的层片状14H-LPSO结构随着冷却速率的下降而增加, 在冷却速率为0.005℃/s的试样中充满了整个晶粒;随着合金冷却速率降低, GWZ1032K合金中晶界第二相分别由5℃/s时的(Mg, Zn)₃RE相转变为0.5 和0.1℃/s时的(Mg, Zn)₃RE相和14H-LPSO结构的χ相共存;在0.01和0.005℃/s时只有14H-LPSO结构的$\chi$相. 结果显示在接近于平衡凝固的缓慢冷速条件下, 更容易形成具有稳定结构的层片状14H-LPSO结构和χ相.在冷却速率为0.5和0.1℃/s时, (Mg, Zn)₃RE共晶相和χ相共存, (Mg, Zn)₃RE共晶相和χ相的位向关系为 [110]_{χ phase}//[223]_{(Mg, Zn)3RE}和∠g(001)_{χ phase} g(110) _{(Mg, Zn)3RE}=8.4°.

关键词: 14H-LPSO结构 , solidification rate , Mg-Gd-Y-Zn alloy , χ phase

Microstructures in advanced materials characterized by HREM and nanoscale analysis

Materials Characterization

Segregation of yttrium induces the formation of Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y microdomains, with L1(2)- and L1(0)-like ordered structures, in ZrO2-6mol%Y2O3 ceramics in both the sintered and annealed states. The compositions of precipitates such as (chi L), (chi S), (chi SS), and small precipitates formed inside XL, in Cu-11.88Al-5.06Ni-1.63Mn-0.96Ti (wt.%) shape memory alloys have been determined. Under electron beam irradiation, four types of dynamic behavior of the G.P. zones were observed in the Al-6.58Zn-2.33Mg-2.40Cu (wt.%) alloy. The G.P. zone and "G.P. zone-like" defect structures were also distinguished. Lattice distortion profile in the GaAs/InxGa1-xAs superlattice and two-dimensional lattice distortion around a 60 degrees dislocation core in the InAs(x)P(1-)x/InP superlattice were determined. (C) Elsevier Science Inc., 2000. All rights reserved.

关键词: shape-memory alloys;zirconia;phase;ti;diffraction;crystal

Studies on DC conductivity and magnetic susceptibility of polyaniline doped with different acids

Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications & Review Papers

We report a comparative study among four kinds of polyaniline (PANI) synthesized with four different kinds of acids, under the same conditions for synthesis; PANI-HCl, PANI-H2SO4, PANI-H3PO4 and PANI-C4H6O6. We measured the temperature dependence of the dc conductivity sigma(dc)(T) and the magnetic susceptibility chi(tot)(T) The room-temperature conductivity of HCl and H2SO4-polyaniline was 5-8 times higher than that of H3PO4 and C4H6O6-polyaniline, in which the values of 18.1, 16.8, 3.8 and 1.85 S/cm were found, respectively. The best fit for our de conductivity data was obtained using the quasi-one-dimensional variable-range hopping (QID VRH) model between nearest neighbors. Polyaniline reported in this paper leads to a high magnetic susceptibility chi(tot) (at T = 295 K) of 10(-4) emu/mol.2rings. This is one or two orders of magnitude higher than those reported earlier for polyaniline. Data on sigma(dc)(T) and chi(tot)(T) are also discussed.

关键词: polyaniline;dc conductivity;magnetic susceptibility;quasi-one-dimensional variable-range hopping;electron localization;charge-transport;emeraldine

时效析出相对铸造2507超级双相不锈钢力学及耐蚀性能的影响

向红亮刘东阮方如何福善黄利光

金属学报 doi:10.3724/SP.J.1037.2010.00143

通过OM, SEM以及拉伸实验与电化学测试等手段, 研究了高温时效析出金属间相对铸造2507超级双相不锈钢力学及耐蚀性能的影响. 实验结果表明: 材料固溶后经650-950 ℃时效处理, 析出弥散颗粒χ相有提高抗拉强度的作用,σ相却使抗拉强度急剧下降; 二者均使塑性急剧恶化, 拉伸断口均表现为脆性断裂. 在人工海水中, σ相对材料的耐蚀性影响要比$\chi$相弱,其数量越多, 材料耐蚀性越差.

关键词: 铸造2507超级双相不锈钢 , intermetallic phase , mechanical roperty , corrosion resistance

壳聚糖-海藻酸聚电解质复合膜 (Ⅰ)激光共聚焦扫描显微镜分析形貌

马莉华 , 于炜婷 , 马小军

膜科学与技术 doi:10.3969/j.issn.1007-8924.2005.02.007

以气体致孔法制备壳聚糖(Chi)-海藻酸(Alg)聚电解质复合膜.用激光共聚焦扫描显微镜(LCSM)观测并分析复合膜的形态结构.结果表明,LCSM无需样品处理即可原位观察Chi-Alg聚电解质复合膜在不同层面上的内部形态结构,通过调整添加剂NaHCO3的用量可以得到平均孔径分布在30～165 μm的复合膜.该聚电解质复合膜作为一种潜在的生物医用材料,有望与细胞、药物及活性因子结合,在组织工程皮肤领域得到应用.

关键词: 气体致孔法 , 壳聚糖 , 海藻酸 , 激光共聚焦扫描显微镜(LCSM)